ToxicMegacolon

Toxic Megacolon,Yanjun Wang First year postgraduate studentThe First Affiliated Hospital of Nanjing Medical University,2016.05.11,Case 1,Symptomatology A 53-year-old man complaint with abdominal pain, bloody diarrhea and fever (up to 39.5) for about one month Physical examination T 38.8, P 100 /min, R 18 /min, Bp 100/60 mmHg periumbilical pain, distention and anasarcaLaboratory investigations Blood RT : WBC 13.5 109/L(), N 79.4% () Stool RT : occult blood test (+), WBC（+） Blood biochemical test : Albumin 18.91g/L(), Kalium 3.30 mmol/L (), Calcium 1.76 mmol/L(), Sodium 132.4mmol/L(),Fig 1A. Plain abdominal film Obvious dilation of ascending, transverse and descending colon with air-fluid level (black arrow) and the widest part was up to 8.8 cm (red line).,Fig 1B-1D. Axial contrast-enhanced CT Fig 1B. dilation of ascending and transverse colon with a nodular luminal contour (arrow)Fig 1C. asites and thickened wall of descending colon with air-fluid levelFig 1D. mural stratification, a target sign (white arrow) and gas bubbles (arrow head) adjacent to the wall are suggestive of pneumatosis,1B,1B,1C,1D,Fig 1E-1G. Coronal contrast-enhanced CT images (venous phase)distension of ascending, transverse and sigmoid colonabnormal haustral pattern and nodular pseudopolypswall thickening of descending colon with sight enhancementascites,1E,1G,1F,Diagnosis Toxic megacolon with ulcerative colitis,Definition,Toxic megacolon is a rare but severe and potentially fatal complication of colitis pathologically defined by inflammation of all the layers of the colonic wall and characterized by total or segmental nonobstructive colonic distension of at least 6 cm, associated with systemic toxicity,Simple anatomy of colon,Haustrum,Taeniae coli,Cecum,Ascending colon,Hepatic flexure,Spleenic flexure,Transversecolon,Omentalappendices,Sigmoid colon,Rectum,Anal canal,Appendix,Ileum,Epidemiology,Toxic megacolon may be present at any age and affects both sexesNo precise incidence rate is available for TM, and it varies depending on etiology and population,Inflammatory bowel disease Ulcerative colitis - most common Crohns diseaseInfectious Clostridium difficile - Pseudomembranous colitis Salmonella, Shigella, Yersinia, Campylobacter, E. coli Cytomegalovirus Rotavirus Entameba Aspergillosis Cryptosporidium,Etiology,Ischemic colitisMalignancy Kaposis sarcoma; Colonic LymphomaPotential triggers and exacerbating factors Hypokalemia, hypomagnesemia Barium enema Discontinuation of steroids Narcotics Anticholinergics Chemotherapy Colonoscopy,Etiology,Pathogenesis,The precise pathophysiology of toxic megacolon is not fully understood. However, an association between inflammatory conditions of the colon and decreased smooth muscle contractility is well establishedIt is postulated that more severe inflammation and damage to the colonic wall are necessary for the development of TM and the depth of inflammation seems to be correlated with the extent of colonic dilatation,Diagnostic Approach,HistoryPhysical examinationLaboratory investigationsImaging studies,History,Signs of Inflammatory bowel disease and acute colitis Abdominal pain; (Bloody) Diarrhea; Vomiting; Weight loss; History of previous exacerbations; Extraintestinal manifestationsPossible exposure to enteric pathogens Family, environment; Recent travelsMedication, especially Antibiotics; Steroids; Antidiarrheals; Anticholinergics; OpiatesImmune status Chemotherapy, malignancy; HIV,Physical examination,Abdominal pain, tenderness, distensionConstipation, obstipationReduced bowel soundsFeverTachycardia, hypotensionMental changes,Laboratory investigations,Inflammation Elevated white blood cell count Elevated C-reactive protein Elevated erythrocyte sedimentation rateAnemiaElectrolyte imbalancesBlood cultureFecal screening for pathogensStool samples for C. diff. culture and A/B toxin assay,Clinical Criteria (by Jalan et al.),Main criteria (at least three of the following) Fever ( 38.6 ) Tachycardia ( 120/min) Leukocytosis ( 10.5109/L) AnemiaIn addition at least one of the following Dehydration Altered level of consciousness Electrolyte imbalances Hypotension Imaging studies,Imaging studies,Plain abdominal radiographs are crucial for the diagnosis as well as for the day-to-day monitoring of patients with TMBecause of the high risk of perforation, contrast enema is contraindicated in TMCT is helpful in confirming the development of toxic megacolon and is particularly useful in detecting life-threatening abdominal complications,Plain abdominal radiographs,The transverse or right colon is usually the most dilated colonic segment, frequently more than 6 cm and not rarely up to 15 cm on supine films; Distension of the left colon is less frequent, and distension of the sigmoid colon and rectum is quite rareColonic air fluid levels are often present on upright films and the normal haustral patterns may be absentDistension of small bowel and stomach could be a predictor of TM,CT,Circumferential thickening of the wall of the colon with a diffuse distributionEdematous submucosal changes with the multilayer appearance (target sign)Thickened haustral folds with parallel bands of high and low attenuation (accordion sign)Pericolic stranding and ascitesCT can find some complications, such as peforation, abcess or ascending pyelophlebitis,Hirschsprungs diseaseIntestinal pseudo-obstruction,Differential Diagnosis,Hirschsprungs disease,Hirschsprungs disease (HD) is a congenital absence of ganglion cells of the submucosal and myenteric plexus of the bowel, which begins at the internal anal sphincter and can extend to varying distancesIt is usually diagnosed in the newborn period, with usual presentation of delayed passage of meconium and abdominal distension, with or without bilious vomitingHD in adults is rare and is thus often undiagnosed or misdiagnosedAdult HD generally refers to cases in which the diagnosis is made after the age of 10 years,Hirschsprungs disease,In most cases, symptoms began in the neonatal period with ongoing constipation that was only temporarily relieved by the use of laxatives or enemas. Most of these patients presented with lifelong constipation, abdominal distension and abdominal painThe diagnosis was made by a combination of studies including proper medical history and examination, contrast enema, anorectal manometryand full-thickness rectal biopsies,Hirschsprungs disease,The principal of radiographic findings: a marked dilated colon a smoothly narrowed rectum a cone or funnel shaped transitional segment,Case 2,Symptomatology A 23-year-old man complaint of abdominal distension without flatus and defecation for about 7 days He had a history of suffering from the symptoms,Fig 2A. Plain abdominal film showed obvious distension of colonFig 2B. Barium enema image showed dilated decending and sigmoid colon, and narrowed segment (arrow),2A,2B,Fig 2C-2D. Sagittal and coronal reconstructive CT imagesnarrowed rectum (arrow)marked dilated descending and sigmoid colon,2C,2D,Pathology diagnosis,Specimen taken from the neonate intestinal wall in H + E staining showed marked decrease of ganglion cells, so it was confimed to Hirschsprungs disease,Intestinal pseudo-obstruction,Acute colonic pseudo-obstruction (ACPO) and chronic intestinal pseudo-obstruction (CIPO) are distinct clinical entities in which patients present similarly with symptoms of a mechanical obstruction without an occlusive lesionACPO occurs mainly in the elderly with underlying co-morbidities, while CIPO is a rare syndrome affecting the paediatric and young adult population, accounting for 20% of adult chronic intestinal failureThe majority of ACPO patients are middle-aged or elderly,Intestinal pseudo-obstruction,Approximately 95% have an underlying associated condition with the idiopathic form comprising a small proportion. The condition can be divided into operative and non-operative causes. It commonly follows trauma, pelvic or spinal surgery, other orthopaedic surgery, and Caesarean section. It can also be the sequelae of any infection and normal pregnancyIn contrast, the majority of CIPO cases are idiopathic,Clinical features and diagnosis,The clinical features of pseudo-obstruction are typical of mechanical obstruction; abdominal distention, pain, nausea and/or vomitingPhysical examination reveals a very distended, tympanitic, non-tender abdomen with high pitched tinkling, reduced or absent bowel soundsDiagnosis can be confirmed by demonstration of colonic dilation with an abdominal X-ray and exclusion of mechanical obstruction by CT and enteroscopy,Case 3,Symptomatology A 78-year-old female complaint of periumbilical pain with nausea and vomiting for about one month,Plain abdominal film showed colonic distension Abdominal CT examination and enteroscopy confirmed that there was no obstruction,Clinical diagnosis,Intestinal pseudo-obstruction,Management of Toxic Megacolon,General Intravenous fluid support Correct electrolyte abnormalities Complete bowel rest Discontinue anticholinergics and narcotics Rule out infectious etiologyDecompression Rectal tube Nasogastric or long nasointestinal tube Repositioning maneuvers,Management of Toxic Megacolon,Medical care Specific treatment for infections Intravenous corticosteroids for inflammatory bowel disease Broad spectrum antibioticsRadiology Frequent assessment with plain films Computed tomographic scanning may aid in managementSurgical intervention Failed medical care Progressive toxi